1. Field of the Invention
The present invention relates to a protection fitting for an overhead transmission line, and in particular relates to a rigid-collision-free transmission line spacer clamp connection structure.
2. Description of the Prior Art
In an overhead transmission line, a spacer serves to prevent flagellation between sub-conductors in a bundle and resist aeolian vibration and subspan oscillation, etc. The spacer mainly includes a frame body and a connecting clamp connected to a frame. A clip of the connecting clamp is used for clenching the sub-conductors in the bundle, and the clip is rotated a certain angle along a tangential direction under the action of an axial torsional force of the conductor through a limiting structure at the joint between the frame body and the connecting clamp.
According to the power industry standards Requirements and Tests for Overhead Line Spacers (DL/T 1098-2009), a spacer should have certain mechanical strength under tests of clamp strength, along-line grip, twisting moment, tension and pressure in the horizontal and vertical directions and the like, and should also have certain resistance against vibration fatigue.
The clamp clip of the spacer grips the sub-conductors in the bundle through a rubber sheet with a pad. In this way, the sub-conductors in the bundle can be fixed so that the conductor does not displace along the direction of the line during aeolian vibration or galloping of the conductor, and also a small amount of energy generated during aeolian vibration can be dissipated on the elastic gasket. However, the existing rubber gasket is only provided with one cylindrical clamping block, and the spacer often drops out of the spacer clip during transport, installation and use.
At the joint between the frame and the clamp of the existing spacer, in most cases, a limiting boss structure is arranged on the frame or a kidney hole is formed at the joint, so that the clamp can be rotated a certain angle along a tangential direction under the action of an axial torsional force of the conductor, i.e. the frame body and the spacer connecting clamp body tail being in direct contact, and using a hard connection configuration. During galloping of the conductor, subspan oscillation and conductor vibration in other forms, the spacer is subject to the torsional force and bending forces from different directions, and the hard connection structure suffers from severe collision, which is very likely to cause abrasion or even rupture and damage of the limiting structure at the joint between the clamp and the frame. If galloping occurs again in the line after the spacer is damaged, it may result in broken strands or abrasion of the conductor near the spacer, and may even lead to rupture of the conductor when it is serious, thus causing great harm to the line operation.